January 11, 2018
What’s the diagnosis?
When you first start seeing patients in pain, you are very focused on reaching your diagnosis. You know what can go wrong with the body and there are a number of options available to you; a tendinopathy, a strain, a sprain, a bursitis, a disc, a joint capsule, the list goes on. Unless the therapist has access to scans and imaging, the diagnosis will be based on clinical tests, experience and a degree of hunch. No two presentations of pain are the same and, therefore, the diagnosis is never black and white.
For patients in pain, there is a desire and demand to know what the problem is. What injury do I have, what muscle is torn, what ligament is sprained?
The reality is, however, that even in cases of severe pain, a damaged body part may not be the cause. Pain can be present both in the presence and in the absence of damage. This is an important concept for both patients and practitioners to understand.
Pain vs Injury:
There are plenty of accounts of people in extreme circumstances suffering severe injury, yet reporting of little to no pain. In such moments of extreme stress or danger, it sometimes just doesn’t make sense for the body to be in pain. The need to escape danger, for example, may be prioritised.
The opposite of this can also be true. Severe pain can be experienced when there is no tissue injury. In fact, the pain of a severe injury may even take hold after an injury has healed.
There is no correlation between pain levels and the extent of tissue injury. Pain can be present without tissue injury and tissue injury can be present without pain.
Pain – your danger alarm system
In your nervous system, there are millions of sensors. These sensors are scanning their area of the body for information. Different sensors are specialised in picking up particular bits of information; such as mechanical changes, temperature changes and chemical changes.
These sensors are like little foot soldiers who must report back to the control system (the brain) when they sense a change in their environment. Their reports are actually very simple, for example, “increased heat in my area” or “danger in my area”. The more complex sensations that we feel (for example; tearing, burning or straining) are actually a presentation of the brains interpretation of events – derived from sensor reports but also other factors that the brain is aware of, such as circumstance and past experiences.
The sensors and, therefore, the body’s tissues have no ability to create pain by themselves. There is no direct pain signal that is being sent to the brain by these sensors, neither is there a specific damage or injury sensor that is keenly reporting back on every strain and sprain. The brain must decide for itself whether the signals that it is receiving are sufficient enough for a pain response. This pain response is a tool used by the brain to protect the area of the body it perceives to be in danger. By producing pain, the brain is asking you to protect the area and move away from the danger.
Pain in the absence of injury
So, what are some examples of the brain emitting a pain response without the presence of injury? As you sit and read this blog, you may currently be experiencing such an event. If you are slightly rolling forward through the shoulders, you may be putting the muscles of your upper back under stretch. The mechanical receptors in the muscles will be sending an “I am stretched” signal back to brain. The brain will acknowledge this but won’t initially deem it necessary for a pain response.
As the blog goes on, the continued stretch in these muscles may cause the small blood vessels to become restricted, thereby decreasing the blood flow to the muscle cells. Without adequate oxygenated blood, chemical receptors may begin to pick up a by-product of anaerobic cell activity – lactic acid. The signal sent will be “acid in my area”. The brain now has two messages and may begin to become more interested in this unfolding story.
As the muscles in the upper back become further overloaded and undersupplied with oxygenated blood, micro pockets of inflammation may begin to be triggered, potentially increasing the temperature around the heat receptors in the muscles. An “increased heat in my area” message is sent.
The brain has now had enough reports from its receptors in the upper back to feel that pain is an adequate response. The action that this pain is intending to create is – “get up please and move around!“
This is a very simplified and common example that we all will have experienced. The process can be essentially the same, however, even for more severe experiences of pain. Our bodies are constantly striving to create efficient movement and by doing so they are often over compensating in certain areas to make up for a lack of movement or strength in others. Certain muscles may be overloaded and the body’s various receptors will be picking up on this. The brain may initially not see these messages as enough to trigger a pain response. A small event, however, such as an awkward reach or a change of exercise behaviour, may push the brain over its tipping point and a painful response may be triggered.
Tissue damage in the absence of pain
Leaving severe injury and extreme stress to one side, it is perhaps more interesting to explore how less severe tissue damage in our bodies is often present without pain. Some of the more commonly known back injuries are those involving our discs. An MRI may often be requested in order to identify any changes in our discs that may be causing our painful lower backs.
Although a disc herniation or prolapse can indeed cause pain and irritation of surrounding tissue, it is not a definitive cause of pain. Remember, that the tissues themselves cannot transmit pain; it is the brain that must decide whether the messages from the area warrant a pain response.
Studies performed on patients with no back pain, have shown that 65% of those studied have abnormal changes in their discs, yet no pain was present. A similar study showed that 25% of patients with no back pain had nerve compression from a bulging disc, again no pain was present.
These studies are an example of how our bodies regularly cope with tissue damage, without deeming it necessary for us to be in pain.
Nothing on the MRI – what next?
So, why does this matter? Very often, patients will report that although being in pain, they have had an MRI or X-Ray and everything seems to be normal. In traditional medicine, the next steps are unclear. If there is no specific diagnosis of a damaged tissue, then the options for treatment narrow. You may be given pain killers or referred for physio to improve your strength or mobility. Some patients in these circumstances are made to think that the pain is “in their head” and they may start to doubt their own symptoms and restrictions.
As we now know, pain is manifesting in the brain, so is most certainly “in the head” but this does not mean that it is not very real! We, as practitioners, have to look beyond the site of pain for the reasons why these (seemingly undamaged tissues) are having such a hard time of things. Tissues are often overloaded, underworked, restricted or dysfunctional. None of these things will show up on an MRI. In order to understand these presentations, we need to look at the source of dysfunction, the reasons why a tissue is overloaded, for example.
We need to understand that the lower back may be overworking and in pain, due to a lack of hip mobility. We need to understand that a shoulder may be dysfunctional due to reduced upper back function. If we keep scanning the area of pain and hunting for tissue damage, then we may often be looking in the wrong area.
This also goes the other way. If we have been diagnosed with a disc herniation or a tendinitis of some description, then we should not see this as the end of pain free movement and the active life that we once enjoyed. Sometimes the problem with a diagnosis is that it can create an anxiety about the patient’s ability to successfully perform certain movements or tasks using the affected area. These changes in behaviour can then compound the problem. Or bodies can cope with tissue damage or degeneration, as long as we have the mobility, strength and confidence to allow our bodies to move successfully.